Many people said it couldn't be done but, with the help of a very nice and knowledgeable bike shop owner, we were able to make some minor modifications (nothing irreversible) and come out with the gearing I wanted. And the chain has the perfect tension! I used that HTML fixie gearing chart from peak.org and came up with the options that would work. We used an IRO flip flop hub and had to add and move a few washers/spacers around to get good alignment but it worked. And not only that, the chain tension and alignment came out right on the nose. We could'nt even have gotten it any more percise if we had been working with horizontal drop-outs! I'm VERY HAPPY!! Can you tell? I'm just elated because I was able to use the frame (my 1200) that I have really grown to love. The whole setup just fits me so well that the thought of having to use a different frame just bummed me out. But this local bike shop owner said it was possible and so I gave it a shot and it worked great!
Now don't get me wrong, there were limited gearing options but it just happened that my preferred setup was one that worked. I am using the 42 on the front and a 14 on the rear. It's a little higher gear than normal on a fixie (or so it seems from my limited experience) but it gives me the ability to go prety fast but still hit most hills around town. Now sometimes I might wish it was a little lower for some of the bigger hills but then on the flats and down hills I really like it. And I figure it will just make me a stronger rider.
And I am loving how light my bike feels now! And SO clean and simple and QUIET! And effecient! I rode it for the first time as a fixie today and I found that it seemed accelerate much faster. I guess it's because EVERY bit of power is going directly to the road. Pretty Cool.